To reproduce:
1. Open the attached “IN-115065_DeferredMixedLightingBug.zip“ project
2. Open the “Assets/Scenes/DeferredMixedLightingBug.unity” Scene
3. Note that the “Spot Light” GameObjects have their "Mode" set to "Mixed"
4. Note that the “Decal Projector” GameObject has its "Rendering Layers" set to "Default"
5 Note that the “Sphere” GameObjects have their "Rendering Layer Mask" set to "No Decals"
6. Observe the Scene view
7. In the "Decal" renderer feature in the "Assets/Settings/PC_Renderer.asset", enable "Use Rendering Layers"
7. Observe the Scene view

Expected result: The decal no longer covers the spheres, but nothing else changes
Actual result: The decal no longer covers the spheres, but the mixed lighting also disappears

Reproducible with: 6000.0.58f1, 6000.1.16f1, 6000.2.5f1, 6000.3.0b2

Reproducible on: M1 Max MacOS 15.5, Windows 10 (Tested by CQA)

Note:
- This issue is only present with the “Deferred“ and “Deferred+“ Rendering Paths
- “Metal: Error creating pipeline state (Hidden/Universal Render Pipeline/ClusterDeferred): input of type float4 is not compatible with a MTLPixelFormatR8Uint color attachment. (null)“ Error is also thrown when using “Metal“ Graphics Backend

Workaround: Enable "Use Rendering Layers" in the advanced properties in the "Lighting" tab in "PC_RPAsset.asset",
iterate through all lights in the project, and change their "Rendering Layers" from "Default" to "Everything"